scilab/modules/signal_processing/help/en_US/wfir.xml

   1 <?xml version="1.0" encoding="UTF-8"?>
   2 <refentry xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:svg="http://www.w3.org/2000/svg" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:db="http://docbook.org/ns/docbook" version="5.0-subset Scilab" xml:lang="en" xml:id="wfir">
   3   <refnamediv>
   4     <refname>wfir</refname>
   5     <refpurpose> linear-phase FIR filters</refpurpose>
   6   </refnamediv>
   7   <refsynopsisdiv>
   8     <title>Calling Sequence</title>
   9     <synopsis>[wft,wfm,fr]=wfir(ftype,forder,cfreq,wtype,fpar)</synopsis>
  10   </refsynopsisdiv>
  11   <refsection>
  12     <title>Arguments</title>
  13     <variablelist>
  14       <varlistentry>
  15         <term>ftype</term>
  16         <listitem>
  17           <para>
  18             string : <literal>'lp','hp','bp','sb'</literal> (filter type)
  19           </para>
  20         </listitem>
  21       </varlistentry>
  22       <varlistentry>
  23         <term>forder</term>
  24         <listitem>
  25           <para>
  26             Filter order (pos integer)(odd for <literal>ftype='hp'</literal> or <literal>'sb'</literal>)
  27           </para>
  28         </listitem>
  29       </varlistentry>
  30       <varlistentry>
  31         <term>cfreq</term>
  32         <listitem>
  33           <para>
  34             2-vector of cutoff frequencies (<literal>0&lt;cfreq(1),cfreq(2)&lt;.5</literal>)  only <literal>cfreq(1)</literal> is used when <literal>ftype='lp'</literal> or <literal>'hp'</literal>
  35           </para>
  36         </listitem>
  37       </varlistentry>
  38       <varlistentry>
  39         <term>wtype</term>
  40         <listitem>
  41           <para>
  42             Window type (<literal>'re','tr','hm','hn','kr','ch'</literal>)
  43           </para>
  44         </listitem>
  45       </varlistentry>
  46       <varlistentry>
  47         <term>fpar</term>
  48         <listitem>
  49           <para>
  50             2-vector of window parameters. Kaiser window <literal>fpar(1)&gt;0 fpar(2)=0</literal>. Chebyshev window  <literal>fpar(1)&gt;0, fpar(2)&lt;0</literal> or <literal>fpar(1)&lt;0, 0&lt;fpar(2)&lt;.5</literal>
  51           </para>
  52         </listitem>
  53       </varlistentry>
  54       <varlistentry>
  55         <term>wft</term>
  56         <listitem>
  57           <para>time domain filter coefficients</para>
  58         </listitem>
  59       </varlistentry>
  60       <varlistentry>
  61         <term>wfm</term>
  62         <listitem>
  63           <para>frequency domain filter response on the grid fr</para>
  64         </listitem>
  65       </varlistentry>
  66       <varlistentry>
  67         <term>fr</term>
  68         <listitem>
  69           <para>Frequency grid</para>
  70         </listitem>
  71       </varlistentry>
  72     </variablelist>
  73   </refsection>
  74   <refsection>
  75     <title>Description</title>
  76     <para>
  77       Function which makes linear-phase, FIR low-pass, band-pass,
  78       high-pass, and stop-band filters
  79       using the windowing technique.
  80       Works interactively if called with no arguments.
  81     </para>
  82   </refsection>
  83 </refentry>